thesisIt has been shown by Edwards et al., Magnusson, Takeya, and others that delayed skin reactions engendered in guinea pigs are a valuable means of differentiating mycobacterial species and types. In the studies here reported the close relationship of avian and Battey bacilli in confirmed. Nevertheless, skin sensitivity of guinea pigs inoculated with various strains of GroupII-avian complex, clearly segregate these bacteria into 3 subgroups: (1) M avium strains, which regularly give a significantly greater reaction to aviin; (2) soil and water strains which sensitize to a minimal degree if at all; and (3) the Battey strains which sensitize about equally to aviin and batteyin. It appears highly improbable that the strains from soil or water, here tested, could be the source of so-called Battey disease or a batteyin skin sensitivity in man. The same is true of some strains from healthy people. But some strains from each of these sources, including people, Australian swine, and Japanese dogs yielded bacteria of the same sensitizing capacity as strains from patients. Twelve pigmented strains became segregated by our studies into 3 subgroups: (1) strongly, (2) weakly, and (3) nonsensitizing to scotochromin, the PPD prepared from a lymph node strain. Only the first subgroup, the strongly sensitizing, was related to disease. Biochemical properties of the mycobacteria investigated proved variable and failed to provide a basis for further subdivisions. However, urease activity may be helpful as Group II scotochromogens isolated from disease were urease-negative
